This invention relates in general to drive train systems for transferring rotational power from a source of rotational power to a rotatably driven mechanism. In particular, this invention relates to an improved structure for a driveshaft assembly, such as for use in a vehicular drive train system, that is axially collapsible in a reliably controlled manner in the event of a collision.
Torque transmitting shafts are widely used for transferring rotational power from a source of rotational power to a rotatably driven mechanism. For example, in most land vehicles in use today, a drive train system is provided for transmitting rotational power from an output shaft of an engine/transmission assembly to an input shaft of an axle assembly so as to rotatably drive the wheels of the vehicle. To accomplish this, a typical vehicular drive train system includes a hollow cylindrical driveshaft tube. A first universal joint is connected between the output shaft of the engine/transmission assembly and a first end of the driveshaft tube, while a second universal joint is connected between a second end of the driveshaft tube and the input shaft of the axle assembly. The universal joints provide a rotational driving connection from the output shaft of the engine/transmission assembly through the driveshaft tube to the input shaft of the axle assembly, while accommodating a limited amount of misalignment between the rotational axes of these three shafts.
A recent trend in the development of passenger, sport utility, pickup truck, and other vehicles has been to design the various components of the vehicle in such a manner as to absorb energy during a collision, thereby providing additional safety to the occupants of the vehicle. As a part of this trend, it is known to design the drive train systems of vehicles so as to be axially collapsible. To accomplish this, the driveshaft tube may be formed as an assembly of two or more components that are connected together for concurrent rotational movement during normal operation, yet which are capable of moving axially relative to one another when a relatively large axially compressive force is applied thereto, such as can occur during a collision. A variety of such axially collapsible driveshaft assemblies are known in the art. However, in known axially collapsible driveshaft assemblies, it has been found to be relatively difficult to reliably control the manner in which the axially collapsing movement of the driveshaft assembly occurs. Thus, it would be desirable to provide an improved structure for a driveshaft assembly, such as for use in a vehicular drive train system, that is axially collapsible in a reliably controlled manner in the event of a collision.